Conventional paint plants for painting motor vehicle bodies usually have a paint line with several paint booths spatially separated and arranged one after the other in which the individual paint layers are applied to the vehicle body, such as the electrophoretic dip coat (ETL), the filler, the basement and finally the clearcoat. The vehicle body is transported on a rail along the paint line in stop-and-go operation from paint booth to paint booth. When the individual paint layers are applied in the specific paint booths, the vehicle body is located spatially while the application device, such as a rotary atomizer, performs a painting motion, so that the entire surface of the vehicle body is coated by the application device. In the painting process the vehicle body does not move, while the application device moves.
Also when painting body components for vehicles, the body components are usually attached to a product carrier and positioned with a transportation device in stop-and-go operation in front of the appropriate application device, where the application device then performs a painting movement so that the entire surface of the particular component is painted. In this instance also, the component to be painted is spatially fixed during the paint operation while the application device is moved.
The prior art just described has many disadvantages which will be described in what follows.
One disadvantage is that because of the high speed of the application device movement during the painting process, losses in transfer efficiency result which are caused firstly by a movement-induced spray pattern deformation and secondly result from the high percentage of vertical paint applications.
A further disadvantage of the known paint installations is that in the individual paint booths optimal flow conditions are required in a spatially large area to achieve good paint results.
In addition, the paint booth in the known paint installations must be very large in order to avoid contamination of the booth walls from overspray.
Further, the painting speed when painting is limited due to air resistance which affects the moveable application device, or the associated application robot respectively.
Furthermore, the problem exists that the application device has to be supplied through hoses which have to be routed through the associated application robot so that hose size is restricted because of the routing through the application robot.
The hoses routed through the application robot to supply the application device are exposed to great mechanical strain because of the highly dynamic movement of the application robot, which reduces the service life of these hoses and increases maintenance costs.
Further, in the case of the application robots described initially, relatively long hose lengths and large diameters are required, which results in large paint and purging losses.
In addition, the hose routing through the application robot is complex in design, which increases the manufacturing costs for such application robots.
Beyond that, such application robots are also substantial in size since the application equipment has to be housed completely within the application robot.
Overall, this results in expensive robot and application equipment, which increases the investment costs for the customer.
In the case of the conventional painting of body components for motor vehicles described initially, there is the additional problem that for capacity reasons mostly several body components are assembled on a common component carrier. This can cause mutual influencing of the individual components when painting, which worsens the coating quality. In addition, the painting conditions inside the paint booth are not the same for all components. As a result, relatively complex suspended designs are usually required as component carriers, which additionally increases costs. Furthermore, complex studies are needed on the reachability of the individual components and cycle times in order to achieve a satisfactory painting result.